In a vast number of technological fields, a rotatable support of a shaft (or a similar device) in a mounting device is necessary. As an example, rotatable shafts have to be rotatably supported in some kind of housing or holding arrangement for conveyor systems, wheels for vehicles and all kinds of generators, pumps and motors. As a particular example, in the field of pumps or motors, a crankshaft (on which usually some kind of pistons are arranged) has to be rotatably supported in a mounting area of a housing (where the mounting area can be a blind hole or a through hole, as an example).
For making the device as efficient and as durable as possible, the friction of the respective bearing arrangement (rotatable support of the shaft in the mounting area) has to show as little friction as possible, while keeping an eye of economic feasibility at the same time, of course.
For providing a low frictional, durable and still economical support that is able to support comparatively high loads, different types of bearings are in use. Besides the less favourable slide bearings (which usually have a low friction due to some lubricants in the space between the supporting surfaces of the shaft and the mounting device), in particular ball bearings and roller bearings are employed, the latter ones particularly, if higher demands for low friction and/or low wear are present.
Although such bearings work well in practice, they still show some disadvantages, in particular under certain operating conditions. A problematic condition that frequently occurs in practice is if the mounting area (which is generally typically as some kind of a tubular bore (e.g. a blind bore or a through bore)) and the shaft are not perfectly aligned to each other with respect to their longitudinal axis, but instead show an angular misalignment. In particular in case of roller bearings, even relatively small angular offsets can result in a comparatively high wear of the rollers of the roller bearings. Of course, such an increased wear will result in a significantly lower durability of the respective device, which is not really desired.
To overcome this disadvantage, sometimes ball bearings are suggested. However, ball bearings typically show a lower load capacity as compared to needle bearings of the same size, or described vice versa, they need more installation space for the same mechanical load capacity. This is disadvantageous, of course. Furthermore, even if ball bearings are employed, they usually can only sensibly be employed up to a certain angular offset.
Another approach is to “artificially enlarge” the diameter of the shaft and the corresponding mounting bore, although the corresponding enlarged dimension is not necessary from a viewpoint of the loading capacity of the respective device. This is, because when employing a larger diameter of the shaft, a certain offset in a radial direction at a position spaced from the bearing arrangement (measured in length units like millimeters) will result in a smaller angular offset. It is clear that this approach is disadvantageous as well, since it results in increased installation space and in increased weights of the respective components, which usually leads to lower energy efficiency as well. Sometimes increasing the size is not even an option, if certain size restrictions apply.
Therefore, an improved bearing arrangement is required that is less prone to wear due to angular offsets.
This invention provides such a useful bearing arrangement that is improved over bearing arrangements that are known in the state of the art.